Mercury vapor lamp



June 5, 1934. J M S N 1,962,106

MERCURY VAPOR LAMP Filed March 3, 1932 ATTO RN EYJ' Patented June 5,1934 MERCURY VAPOR. LAMP Allison J. Thompson, Cleveland, OhioApplication March 3,

4 Claims.

This invention relates to mercury vapor lamps wherein the luminouselement is mercury vapor in a highly evacuated tube of glass or quartzformed between a mercury cathode and an anode of metal not attached bymercury or its vapor or depreciated by an arc in the latter.

The functioning of such a lamp depends upon current flow with arcuatecharacteristic through mercury vapor, which in turn depends upon thevaporization of mercury from the cathode. The flow once established, itsmaintenance presents no problem but striking the arc has heretoforerequired a special manipulation as by tilting the container to providean instant contact of the cathode with the anode. Provision for thisstarting operation has in turn materially limited the form and size ofthe container by which are determined these characteristics of theluminescent source.

The object of this invention is to remove such limitations, and morespecifically to this end to provide means for producing mercury vaporwith-.

in the container, dependent merely upon supply to the lamp of propercurrent at the proper voltage.

More specifically, the invention embraces in a lamp of the classdescribed, an evacuated container with a pair of separated terminals, amercury cathode associated with one of said terminals, and conductormeans including a heater element, arranged in said container to connectsaid cathode with the terminal removed therefrom, whereby when theproper current is supplied to said lamp by way of said terminals, flowwill be by way of said heater element until sufficient mercury isvaporized to support current flow, and thereafter substantial flow willbe by way of said mercury vapor.

Reference is made to my copending application, Serial No. 588,394, filedJanuary 23, 1932, wherein is disclosed another but comparablearrangement for operating a lamp of this kind.

Another object of the invention is to provide a form of container, madepossible by the arcproducing arrangements of my two applications. whichshall be of large luminescent body and be otherwise in advance of theprior art.

Still another object of the invention is to provide improved mountingmeans for the novel lamp disclosed herein.

The exact nature of this invention together with further objects andadvantages thereof will be apparent from the following description takenin connection with the accompanying drawing, in which Figs. 1, 2 and 3are front, side and top 1932, Serial No. 596,462

views respectively, of an embodiment of the invention, parts beingbroken away in Fig. 1 to show details of construction; Fig. 4 is adetail section as in the plane of line 4-4, Fig. 1.

With reference now to the drawing, the lamp comprises a container 1 ofglass or other lightconducting material, and which may preferably be ofbulbous form with its extremities 2 extended cylindrically as indicated.The lower end 2 of the container forms a cavity within which is provideda quantity 3 of mercury sufficient to provide a supply of mercury vaporfor the hollow of the container. A metal cap 4 is preferably pro videdoutside the container and a terminal 5 is arranged through the end ofthe container to provide electrical connection with the mercury 3, andat the same time provide a seal for maintaining the vacuum in thecontainer.

The opposite extremity 2 of the container is similarly provided with'asealed terminal 6.

Conductor means are arranged to provide a high resistance circuitbetween the terminals 5 and 6 and may preferably include an uppersection 7 of low resistance, and therebelow a heater section 8 of highresistance preferably terminating in convolutions 9 extending well belowthe liquid level of the mercury 3 and serving to position the lower endof the member 8 in the lower extremity of the container 1.

The container being properly evacuated, when the proper current at theproper voltage is applied to the terminals 5 and 6, a circuit will behad between the terminals by way of the conductor sections 7 and 8. Thelatter and particularly the unsubmerged convolutions 9 thereof,

provides a heater element which causes vaporization of the mercury 3.The mercury vapor rises generally along the conductor until it reachesthe section '7 thereof. Thereupon a vapor conductor is completed, whichultimately has sufficient capacity to support current flow, the mercuryacting as the cathode element as usual in mercury vapor lamps. Withformation of the are thus formed a large part of the flow between terminals will be had by way of the mercury vapor and as the arc is builtup by further vaporization of the mercury, more and more flow will be byway of the vapor and less by way of the conductor, the resistance of thesection 8 of which is relatively high as compared with that of themercury vapor. Thus, when the lamp is in operation there is a dividedcircuit partly through the conductor but largely through the mercuryvapor in parallel relation/ therewith.

That the lamp may have suitable support in its operating position, Iprovide mounting means therefor. The principal parts of the mountingmeans are a pair of opposed sockets 10 and 11, and arms 12 and 13Joining the sockets and bowed outwardly as in Fig. 1 to clear thecontainer 1, the mount being thus generally in the form of a frame aboutthe lamp. I

This frame may be made of sheet metal in two pieces, each pieceincluding one-half part of both sockets and both arms, the planeofdivision between the pieces being vertical and central of the lamp. Asshown in Fig. 4 the arms have grooves cooperable to form a passage 14connecting the hollows of the sockets l0 and 11. The pieces are securedto form an integral whole as by spot welding at intervals as indicatedat 15.

The cavity of the upper socket 11 is of sufficient depth to take thehead 16 of a threaded nipple 17 by which the frame may be hung. Thenipple and frame are rigidly secured as by welding as indicated at 15a.

An insert 18 of non-conductive material is set into the lower socket 10.Its depth is such that when its flanges 18a are seated, the bottom ofthe insert will be above the level of the passages 14 in the frame. Theinsert has an opening to clear the terminal 5.

The upper socket is similarly provided with an insulating insert 19having a perforation at its end registering with the passage opening inthe nipple l7, and having a lateral opening registerable with thepassage 14. The depth of 'the upper socket, and its spacing relative tothe lower .one is such that the upper extremity of the lamp may first beinserted in the upper socket, the lower extremity of the lamp then swungover and into the lower socket, so that both extremities of the lamp arepositioned in the frame.

Connection to the lamp is had by way of its mount, in the followingmanner: One conductor 20 is led through the nipple 17 and has connectionwith the terminal 6. This connection must be made before the lamp ispositioned in its mount. The other conductor 21 is led through thenipple, through the passage 14 in one of the arms of the frame andthence connected with the lower terminal 5. This connection once madepositively maintains the lamp secured in it mount. Access for makingthis connection is had through the bottom end of the lower socket 10,which is open.

What I claim is:

1. In a lamp of the class described, an evacuated container with a pairof separated terminals, a mercury cathode in conductive relation withone or said terminals, and conductor means arranged in said container toconnect said cathode with the terminal removed therefrom and including aconvoluted heater element adjacent said cathode and there positioned bycooperation with that part or said container which holds the mercury ofsaid cathode.

2. In a lamp of the class described, a container with a pair ofseparated terminals, a mercury cathode in conductive relation with oneof said terminals, and conductor means including a heater element,arranged in said container with a substantial portion immersed in themercury of said cathode, to continuously connect said cathode with theterminal removed therefrom, whereby when the proper current is suppliedto said lamp by way of said.- terminals, flow will be by way of saidheater element until suflicient mercury is vaporized to effect an arc,and thereafter substantial iiow will be by way of said arc.

3. In a lamp of the class described, an evacuated container with anodeand cathode terminals, a mercury cathode in conductive relation with thecathode terminal, and conductor means leading within said container fromthe anode terminal to said cathode and having a part substantiallyimmersed in the mercury of the latter, said conductor means including aheater element.

4. In a lamp of the class described, an evacuated container with anodeand cathode terminals, a mercury cathode in conductive relation with thecathode terminal, and conductor means leading within said container fromthe anode terminal to said cathode ,and having a heater part extendingsubstantially into the mercury of said cathode.

ALLISON J. THOMPSON.

